'Use of Rear Tip Extenders Results in Greater Inflatable ... · "Use of Rear Tip Extenders Results in Greater Inflatable Penile Prosthesis Cylinder Deflection" Eid, J.F. 1, Taylor,

"Use of Rear Tip Extenders Results in Greater Inflatable Penile Prosthesis Cylinder Deflection"

Eid, J.F. 1, Taylor, J. 2 , Cordon, B.H. 3

1: Advanced Urological Care & Northwell Health, USA;2: Coloplast Research and Development, USA;3: Columbia University Division of Urology at Mount Sinai

Medical Center in Miami Beach, FL, USA

Objective:

• To determine whether adding rear tip extenders affect penile prosthesis cylinder stiffness

• To determine whether decreasing the length of the non inflatable solid proximal portion of the cylinder affect penile prosthesis cylinder stiffness

Hypothesis:

Adding rear tip extenders increases the deflection of the erection

Adding rear tip extenders decreases the inflatable portion of the cylinders that is supported by the crus and lengthens the non inflatable proximal portion of the cylinder

Clinical observations:

• Angle of the penis with the inflated cylinders (some point down others up)

• Loosening of the pseudo-capsule that occurs overtime in patients with malleable implants

• Loosening of the pseudo-capsule that occurs over time in patients that leave their cylinders partially inflated

• “Hinge effect” at the junction of the solid cylinder proximal moiety with the inflatable portion; wobbly erection

Current features of the Coloplast inflatable cylinder design:

• Heterogeneous beam (hybrid) composed of non-inflatable narrower solid 5cm proximal structure secured to a wider distal inflatable segment

• When inflated the diameter of the inflatable is greater than the diameter of the solid proximal portion

• The junction between the non and inflatable portion of the cylinder represents a point of mechanical weakness

• The longer the inflatable portion, the greater the diameter expansion when inflated; 22 >20>18cm

• The longer the cylinder, the thicker the sidewall of the inflatable portion of the cylinder

Why is the solid rear tip 5cm in length?

]

Maximizing “Rigidity Factor” of Inflatable Penile

Prosthesis (IPP) Results in Better Artificial

ErectionCordon, Billy H., Eid, J. Francois

Lenox Hill Hospital, New York City, New York

Totalcylinder length

Inflatableportion length

Maximum Rigidity Factor

1cm RTE

2cm RTE

3cmRTE

20cm 15cm 0.75 0.7 0.65 0.6

22cm 17cm 0.77 0.73 0.68 0.64

24cm 19cm 0.79 0.75 0.71 0.67

26cm 21cm 0.81 0.77 0.73 0.61

28cm 23cm 0.82 0.78 0.75 0.71

Defining the concept of the Rigidity Factor

What is the average length of the crus? What is the angle of attachment to the pelvis?

• Index the Instron down on the model, measuring the increase of both deflection and force as it moves.

• Once the desired force is achieved the Instron is stopped and both the force and deflection of the are recorded.

Method:

An Instron machine was used to apply 200g force at the same distance from cylinder base for various cylinder lengths with and without RTE(s)

Results:

• Measurements were taken for 18, 20, 22 cm cylinders

• Additional measurements were taken for 20 and 22cm cylinders with 1 cm amputated from the solid proximal portion

• Adding a RTE increased the deflection • Decreasing the length of the solid proximal

portion of the cylinder decreased the deflection

RTE Deflection Rigidity Factor

0 cm 1.895627 0.72

1 cm 2.751938 0.68

2 cm 3.259099 0.65

3 cm 3.800898 0.62

18 cm IPP @ 15 Psi

RTE Deflection Rigidity Factor

0 cm 3.331058 0.75

1 cm 3.440498 0.71

2 cm 3.576176 0.68

3 cm 3.748642 0.65

-1 cm 2.695541 0.79

20cm Cylinder @ 15 Psi

RTE Deflection Rigidity Factor

0 cm 3.887351 0.77

1 cm 4.053501 0.74

2 cm 4.296952 0.71

3 cm 4.532325 0.68

-1 cm 3.618425 0.81

22cm Cylinder @ 15 Psi

Two weeks post-op Coloplast

in a post robotic prostatectomy

patient

Reservoir Incision

24cm XL cylinders

Limitations

• Study does not take into account the role of the pendulous tunica albuginea

• Study does not take into account the fact that different size cylinders expand to different diameters and have different wall thickness

• This method could not be used to compare different cylinder sizes (22cm vs 20+2cm) see abstract #197

Conclusion:

• Greater bending deflection was associated with the use of greater RTE length

• Use of RTE decreases the inflatable portion of the cylinder that is supported by the crus

• This data supports the notion that minimizing RTEs improves cylinder stiffness and overall erectile rigidity dynamics

• Decreasing the length of the non inflatable proximal portion decreases the bending deflection

• These observations could possibly improve the design of the next generation of cylinders

Thank You!